456 THE UNFINISHED BOOK. [1857. 



more hairy in dry districts, then the case of the varieties 

 becoming more hairy in dry ground would be a fact for 

 me. 



C. Darwin to J. D. Hooker. 



Down, June 3rd [1857]. 



My dear Hooker, — I am going to enjoy myself by 

 having a prose on my own subjects to you, and this is a 

 greater enjoyment to me than you will readily understand, as 

 I for months together do not open my mouth on Natural 

 History. Your letter is of great value to me, and staggers me 

 in regard to my proposition. I dare say the absence of bo- 

 tanical facts may in part be accounted for by the difficulty 

 of measuring slight variations. Indeed, after writing, this 

 occurred to me ; for I have Crucianella slylosa coming into 

 flower, and the pistil ought to be very variable in length, and 

 thinking of this I at once felt how could one judge whether it 

 was variable in any high degree. How different, for instance, 

 from the beak of a bird ! But I am not satisfied with this 

 explanation, and am staggered. Yet I think there is some- 

 thing in the law ; I have had so many instances, as the follow- 

 ing : I wrote to Wollaston to ask him to run through the Ma- 

 deira Beetles and tell me whether any one presented anything 

 very anomalous in relation to its allies. He gave me a unique 

 case of an enormous head in a female, and then I found in 

 his book, already stated, that the size of the head was aston- 

 ishingly variable. Part of the difference with plants may be 

 accounted for by many of my cases being secondary male or 

 female characters, but then I have striking cases with her- 

 maphrodite Cirripedes. The cases seem to me far too numer- 

 ous for accidental coincidences, of great variability and ab- 

 normal development. I presume that you will not object to 

 my putting a note saying that you had reflected over the case, 

 and though one or two cases seemed to support, quite as many 

 or more seemed wholly contradictory. This want of evidence 



